When Nichole Robertson relocated to Paris from New York more than four years ago, she roamed the city.

She soon hit upon a distinctive way of documenting her wanderings.

She took photos of particular colors she found popping out against that characteristic Paris gray, then went on a scavenger hunt to find where in the city those colors -- a certain rust red, say, or eggshell blue -- recurred.

She posted the resulting photographic series on a blog (now archived at Obvioustate.com).

The bestseller

And then the part that doesn't usually happen: the blog went viral and led to a bestselling book, "Paris in Color."

The images are clearly Parisian, but organized in a novel and engaging fashion.

Like so many new arrivals in Paris, Robertson at first traipsed around the city’s most popular sights, such as Notre Dame, the Eiffel Tower and Arc de Triomphe.

She noticed visitors dutifully pulling back to snap pictures of their travel companions in front of these classic attractions and then dutifully putting their cameras away.

Robertson decided to go for an opposite approach: focusing in on detail and color.

She took shots that highlighted the varying shades of brown in a row of baguettes, a bicycle saddle bag and an aged stone building façade, for example.

She focused on yellow as it cropped up in a café façade, a tart in a patisserie or flowers in a window basket.

Capture the details

“The details are the things that you will actually remember -- capture those,” Robertson advises photographers.

She seeks out culture, bits of nature thriving in the city and moments of human interaction.

Neutral grays and browns are featured prominently in her work; bouncing against each other, they feel lively.

Robertson’s color-seeking approach is surprising, given the uniformly neutral shade that prevails in so much of Paris.

Buildings are typically off-white or gray -- an ideal canvas for shocks of color, as well as the more subtle shades, she sought out.

Robertson prefers a dull, overcast sky.

When the sun is shining and the sky is blue, she puts down her camera and heads to a café.

Robertson’s project is, in a sense, all about surface -- surface color -- but she also feels it gives her a sense of the city’s underlying rhythms and quirks.

Shapes or theme

You needn’t just focus on a color, Robertson suggests.

Any repeating shape or theme will do.

Parisian typography, pastries or transportation methods are all good starting points for re-focusing the way you see things.

“It might seem absurd just to wander around Paris,” Robertson says, especially if you have limited time there.

But to really get to know the city she recommends choosing a particular area and doing just that, even for one day, noticing the quirks and repeating themes -- and photographing them.

The same approach works equally well in many other old European cities, such as Rome.

As for Robertson, she returns again and again to Montmartre, the Left Bank, and the banks of the Seine, all of which she also documents in an iPhone app, The Paris Journals.

“Paris gets distilled down to one or two icons that don’t capture all the other equally good stuff you see," she says.